Piston



J. R. HOBBS.

PISTON.

APPLICATION FILED JUNE 15, 1920.

Patented Oct. H, 1921..

TURN ROBERT HOBBS, OF LONDON, ENG-LAND.

ineaasa Application filed June 15,

To all whom it may concern Be it known that I, JOHN ROBERT Hoses,

a British subject, residing at 21 Buller road,

Vensal Rise, London, England, have in vented certain new and useful Improvements in Pistons, of which the following is a specification.

This invention relates to pistons and is primarily intended for pistons for internal ting of pistons in the first instance, and in case of the enlargement of a cylinder bore on re-grinding render it unnecessary to fit a new piston, all that is requisite being to fit oversize rings. The invention consists broadly in a piston comprising a separate head and a detachable skirt 1 or slipper formed in two parts, the line of cleavage preferably being approximately in a plane containing the axis of the cylinder, and the two parts being urged outwardly and away from each other by a spring abutment operating at right angles to the direction of reciprocation of the piston.

The invention is illustrated in the accompanying drawing in which Figures 1 and 2 show side elevations at right angles to each other of the piston head, F i 3 is an elevation of a part of the detacha le skirt, Fig. 4 is an elevation partly in section of the assembled piston, and Fig. 5 is a plan view of Fig. 3.

In carrying the invention into effect according to the preferred form, the piston head 1 is provided with two downwardly extending wings 2 carrying the gudgeon-pin bosses 3 which are also supported from the head by webs. At right angles to the gudgeon-pin. axis is provided a tubular sleeve 4: also supported by a web, the ends of the sleeve being beveled as shown at 5, a number of perforations being provided for lubrication. The head is slotted as shown, there being provided an upper slot 6 of l.-sect10n and a lower rectangular slot 7, the two slots being separated by a narrow flange 8 of smaller diameter than the piston head. T he slipper is formed in twosimilar halves or segments. Each segment at its upper end is provided with a shouldered neck 9 provided with an outwardly directed top flange 10,

Specification of Letters ]Patent.

Patented Get. '11, mail.

1920. Serial No. 389,193.

the neck being machined to fit the slot 7 of the piston head, and the flange 10 to coincide with the flange 8 as shown in Fig. 1. Each segment of the slipper carries an inwardly directed pin 11 enlarged at its base and having a reduced end 12. An internal rib at the lower part of the slipper segments is provided with two bosses 13, 14:, of which one is of larger bore than the other. The bosses are constructed with their axes directed along chords of the sectional circle which are parallel to the axis of the pins 11.

In assembling the piston, the segments are placed in position on the wings 3 with the pins 11 inserted in the tubular passage 4 with the interposition of a spring 15, Fig. 4. A pin 16, Fig. 4 is inserted in each of smaller bosses 18 and forms a sliding fit with a cylindrical housing 17 for a spring 18 which is inserted in a larger boss 14: of the opposing segment, the bosses being situated so as to be in line when the slipper is assembled. The segments are provided with internal flatfaced lugs 19 adapted to seat themselves within flat-bottomed slots 20 in the wings 2 of the piston head.

The piston rings which are shown seetionally alongside Fig. 4 consists of an upper rectangular ring 21 seated in the upper part of the slot 6, and a lower ring 22 of channel section seated astride the two flanges 8, 10, the flanges serving as an additional safeguard to maintain the accurate position of the rings. A third ring 23 is seated near the bottom of the skirt. It is important that the piston-ring joints should lie in a plane at right angles to the axis of the pins 11, the joints 0: the rings 21, 22 being on opposite sides of the piston.

The margin of adjustment in the position of the two segments of the slipper is provided in the machining of the adjoining straight edges, it being understood that the force of the springs 15, 18 is stronger than the restraining force of the three pistonrings.

In the form illustrated the slipper covers the gudgeon-pin ends it being understood that the gudgeon-pin bearing is lubricated under forced lubrication. In the alternative case, the slipper will be holed and the gudgeon-pin fitted with a loose cap to avoid risk of injury to the cylinder wall.

It will be seen that by my invention, T provide a piston capable of a relatively large margin of automatic ad ustment to llltl take up wear in the cylinders or to accommodate itself to expansion, and that the plane of adjustment is properly confined to a plane at right angles to the direction of thrust. Cylinders intended to cooperate therewith may be bored parallel instead of taperingand. if the bore of the cylinder be slightly enlarged during grinding, it is not necessary to fit a new piston as the present piston will accommodate itself to the new bore if slightly oversize rings be fitted. Moreover, the fitting of new pistons in the first instance is greatly facilitated. The range of clearance that is required is governed by the machining of the adjoining verti al edges of the slipper segments and can be regulated to any figure found desirable.

claim l. A piston comprising a head formed with a tubular sleeve and a detachable slipper formed in two parts, each part of the slipper having a pin projecting therefrom to seat in the tubular sleeve.

2. A piston comprising a head formed with a tubular sleeve and a detachable slipper formed in two parts, each part of the slipper having a pin projecting therefrom to seat in the tubular sleeve, a spring ar- *anged in said sleeve to bear against the ends of the pins to exert a spring tension on the slipper parts.

3. A piston comprising a head provided with wings bored to receive a gudgeon-pin, a tubular passage set at right angles to said borings and to the direction of reciprocation of the piston, a detachable slipper formed in two semi-cylindrical halves the lines of separation between the two halves passing over the said borings, each half being provided with a central radial inwardly-directed pin seated in said passage, a spring interposed between the two pins so as to urge the two pins away from each other and sprin means cooperating therewith and interposed between the two halves in the lower parts.

a. A piston comprising a head provided with wings bored to receive a gudgeon-pin, a tubular passage set at right angles to said borings and to the direction of reciprocation of the piston, a rectangular circumferential slot, an L-shaped circumferential slot, a flange of smaller diameter than the cylinder head separating said slots, a detachable slipper formed in two similar halves seated around said head, each half having a central inwardly-directed radial pin seated in said tubular passage, a spring interposed between said pins so as to urge them apart, a neck formed on the upper end of said slipper surmounted by an outwardly-directed flange similar to and situated alongside the said flange on the piston head, hollow bosses formed on the lower internal part of said slipper, said bosses being axially parallel to said radial pins and set opposite to each other in pairs, spring abutments inserted in said bosses cooperating with the aforesaid spring in the tubular passage of the piston head, a piston ring in the upper part of the L-shaped slot, and a second piston ring of channel-section adjoining the said piston ring and seated astride the two flanges.

5. A piston comprising a head formed with a tubular sleeve, a slipper formed in two parts, with each part provided with a pin adapted to seat in said sleeve, and spring means interposed between the slipper parts remote from said pins.

In testimony whereof I afiix mv signature.

JOHN ROBERT HOBBS. 

